Dicing/die-bonding film, method of fixing chipped work and semiconductor device

ABSTRACT

A dicing/die-bonding film including a pressure-sensitive adhesive layer ( 2 ) on a supporting base material ( 1 ) and a die-bonding adhesive layer ( 3 ) on the pressure-sensitive adhesive layer ( 2 ), wherein a releasability in an interface between the pressure-sensitive adhesive layer ( 2 ) and the die-bonding adhesive layer ( 3 ) is different between an interface (A) corresponding to a work-attaching region ( 3   a ) in the die-bonding adhesive layer ( 3 ) and an interface (B) corresponding to a part or a whole of the other region ( 3   b ), and the releasability of the interface (A) is higher than the releasability of the interface (B). The dicing/die-bonding film is excellent in balance between retention in dicing a work and releasability in releasing its diced chipped work together with the die-bonding adhesive layer.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a dicing/die-bonding film. Thedicing/die-bonding film is used for subjecting a work to dicing in sucha state that an adhesive for sticking a chipped work (semiconductor chipetc.) to an electrode material is arranged on a work (semiconductorwafer etc.) before dicing. Further, this invention relates to a methodof fixing a chipped work by using the dicing/die-bonding film. Also,this invention relates to a semiconductor device having a chipped workadhesive-bonded by the fixing method.

2. Description of the Related Art

A semiconductor wafer on which a circuit pattern was formed is subjectedto dice into chipped works (dicing step), as necessary afterback-grinding to regulate the thickness. In the dicing step, thesemiconductor wafer is generally washed at suitable fluid pressure(usually, about 2 kg/cm²) to remove a cut layer. Then, the chipped workis adhesive-bonded onto an adherend such as a lead frame (mountingstep), and then processed in a bonding step. In the mounting step, anadhesive is conventionally applied onto the lead frame or the chippedwork. In this method, however, a uniform adhesive layer is hardlyformed, and application of the adhesive requires a special unit and along time. Accordingly, a dicing/die-bonding film having an adhesivelayer adhering semiconductor wafer thereto in the dicing step andproviding a chip-mounting necessary for the mounting step has beenproposed (see e.g. in JP-A 60-57642).

The dicing/die-bonding film described in JP-A 60-57642 supra comprisesan adhesive layer arranged in a releasable manner on a supporting basematerial. That is, a semiconductor wafer retained on an adhesive layeris diced, and the supporting base material is stretched to remove eachchipped work together with the adhesive layer, and each work isrecovered and fixed via the adhesive layer to an adherend such as a leadframe.

To prevent problems such as dicing inability and dimensional mistakes,the adhesive layer of this dicing/die-bonding film is desired to have anability to sufficiently maintain the semiconductor wafer and an abilityto sufficiently release the chipped work together with the adhesivelayer from the supporting base material after dicing. However, it is noteasy to balance both the abilities. When sufficient retention isrequired of the adhesive layer particularly in a system of dicing asemiconductor wafer with a rotating circular tooth, thedicing/die-bonding film satisfying the above characteristics is hardlyobtained.

To overcome the problem, various improved methods are proposed (see e.g.on JP-A 2-248064). JP-A 2-248064 supra proposes a method which comprisesallowing a UV-curing pressure-sensitive adhesive layer to be presentbetween the supporting base material and the adhesive layer, then curingit by UV rays after dicing to lower the adhesion between thepressure-sensitive adhesive layer and the adhesive layer therebyreleasing the layers from each other to facilitate pickup of the chippedwork.

By this method, however, there are the cases where the adhesive layerachieving retention for the dicing step and releasability for asubsequent step in good balance is hardly formed. For example, when alarge chipped work of 10 mm×10 mm or more is to be obtained, its area isso great that the chipped work cannot be easily picked up with a generaldie bonder.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a dicing/die-bondingfilm comprising a pressure-sensitive adhesive layer on a supporting basematerial and a die-bonding adhesive layer arranged in a releasablemanner on the pressure-sensitive adhesive layer, which is excellent inbalance between retention in dicing a work and releasability inreleasing its diced chipped work together with the die-bonding adhesivelayer.

Another object of this invention is to provide a method of fixing achipped work by using the dicing/die-bonding film. A still other objectof this invention is to provide a semiconductor device comprising achipped work adhesive-bonded by the fixing method.

The present inventors made extensive study to solve the problem, and asa result, they found a dicing/die-bonding film as following described,thus arriving at this invention.

That is, this invention relates to a dicing/die-bonding-film comprisinga pressure-sensitive adhesive layer (2) on a supporting base material(1) and a die-bonding adhesive layer (3) on the pressure-sensitiveadhesive layer (2),

-   -   wherein a releasability in an interface between the        pressure-sensitive adhesive layer (2) and the die-bonding        adhesive layer (3) is different between an interface (A)        corresponding to a work-attaching region (3 a) in the        die-bonding adhesive layer (3) and an interface (B)        corresponding to a part or a whole of the other region (3 b),        and the releasability of the interface (A) is higher than the        releasability of the interface (B).

In the dicing/die-bonding film (1), the adhesion of thepressure-sensitive adhesive layer (2) to the die-bonding adhesive layer(3) is different between a region (2 a) corresponding to thework-attaching region (3 a) in the die-bonding adhesive layer (3)and aregion (2 b) corresponding to a part or the whole of the other region (3b), and satisfies the relationship the adhesion of thepressure-sensitive adhesive layer (2 a) is lower than the adhesion ofthe pressure-sensitive adhesive layer (2 b).

The dicing/die-bonding film (1) of this invention comprises apressure-sensitive adhesive layer (2) on a supporting base material (1)and a die-bonding adhesive layer (3) in a releasable manner on thepressure-sensitive adhesive layer (2). In the pressure-sensitiveadhesive layer (2), the adhesion of regions (2 a, 2 b) corresponding tothe work-attaching region (3 a) and the other region (3 b) respectivelyin the die-bonding adhesive layer (3) is designed such that the adhesionof the pressure-sensitive adhesive layer (2 a) is lower than theadhesion of the pressure-sensitive adhesive layer (2 b). That is, thepressure-sensitive adhesive layer (2 b) adheres suitably to the adhesivelayer (3) during dicing step or expanding step, to prevent the adhesivelayer (3) from being released from the pressure-sensitive adhesive layer(2). On the other hand, the pressure-sensitive adhesive layer (2 a) canbe easily released. Accordingly, a dicing/die-bonding film capable ofeasy release and pickup of a large chip of 10 mm×10 mm or more obtainedas diced chipped work without inferior dicing can be obtained. Thus, thedicing/die-bonding film (1) according to this invention well balancesretention during dicing step and releasability during pickup step.

In the dicing/die-bonding film (1), it is preferable that an adhesion ofthe work-attaching region (3 a) in the die-bonding adhesive layer (3) tothe work and to the pressure-sensitive adhesive layer (2 a) satisfiesthe relationship:

the adhesion to the work is higher than the adhesion to thepressure-sensitive adhesive layer (2 a).

When the adhesion of the die-bonding adhesive layer (3) to the work andto the pressure-sensitive adhesive layer (2 a) satisfies thisrelationship, the die-bonding adhesive layer (3) arranged on the chippedwork after dicing can be easily released from the pressure-sensitiveadhesive layer (2 a).

In the dicing/die-bonding film (1), the part of the region (3 b) otherthan the work-attaching region (3 a) in the die-bonding adhesive layer(3) can be used as a dicing ring-attaching region (3 b′). In thedicing/die-bonding film (1), it is preferable that an adhesion of thedicing ring-attaching region (3 b′) in the die-bonding adhesive layer(3) to the dicing ring and to the pressure-sensitive adhesive layer (2b′) satisfies the relationship:

-   -   the adhesion to the dicing ring is lower than the adhesion to        the pressure-sensitive adhesive layer (2 b′).

When the adhesion of the die-bonding adhesive layer (3) satisfies theabove relationship, the balance between retention during dicing step andreleasability during pickup step is improved.

Further, this invention relates to a dicing/die-bonding film comprisinga pressure-sensitive adhesive layer (2) on a supporting base material(1) and a die-bonding adhesive layer (3) on the pressure-sensitiveadhesive layer (2),

-   -   wherein the die-bonding adhesive layer (3) is arranged as a        work-attaching region (3 a) on a part of the pressure-sensitive        adhesive layer (2), and    -   a region (2 a) corresponding to the work-attaching region (3 a)        in the pressure-sensitive adhesive layer (2) and the other        region (2 b) are different in adhesion and satisfy the        relationship:    -   the adhesion of the pressure-sensitive adhesive layer (2 a) is        lower than the adhesion of the pressure-sensitive adhesive layer        (2 b).

The dicing/die-bonding film (2) of this invention comprises apressure-sensitive adhesive layer (2) on a supporting base material (1)and a die-bonding adhesive layer (3) arranged as a work-attaching region(3 a) in a releasable manner on a part of the pressure-sensitiveadhesive layer (2). The pressure-sensitive adhesive layer (2) isdesigned such that the adhesion of the region (2 a) corresponding to thework-attaching region (3 a) and the adhesion of the other region (2 b)satisfy the relationship: the adhesion of the pressure-sensitiveadhesive layer (2 a) is lower than the adhesion of thepressure-sensitive adhesive layer (2 b). That is, the pressure-sensitiveadhesive layer (2 a) can be easily released. On the other hand, a waferring can be stuck on the pressure-sensitive adhesive layer (2 b) andfixed such that it is not released during dicing step and expandingstep. Accordingly, a dicing/die-bonding film capable of easy release andpickup of a large chip of 10 mm×10 mm or more obtained as diced chippedwork without inferior dicing can be obtained. Thus, thedicing/die-bonding film (2) according to this invention well balancesretention during dicing step and releasability during pickup step.

In the dicing/die bond (2), it is preferable that an adhesion of thework-attaching region (3 a) to the work and to the pressure-sensitiveadhesive layer (2 a) satisfies the relationship:

-   -   the adhesion to the work is higher than the adhesion to the        pressure-sensitive adhesive layer (2 a).

When the adhesion of the die-bonding adhesive layer (3 a) to the workand to the pressure-sensitive adhesive layer (2 a) satisfies the aboverelationship, the die-bonding adhesive layer (3 a) arranged on thechipped work after dicing can be easily released from thepressure-sensitive adhesive layer (2 a).

In the dicing/die-bonding films (1) and (2), the pressure-sensitiveadhesive layer (2) is formed preferably from a radiation-curingpressure-sensitive adhesive, and the pressure-sensitive adhesive layer(2 a) corresponding to the work-attaching region (3 a) can be formed byirradiation with radiations.

Further, this invention relates to a method of fixing a chipped work,comprising the steps of:

-   -   pressing a work onto a die-bonding adhesive layer (3 a) in the        dicing/die-bonding film (1) or (2),    -   dicing the work into chips,    -   releasing the chipped work together with the die-bonding        adhesive layer (3 a) from the pressure-sensitive adhesive layer        (2 a), and    -   fixing the chipped work to a semiconductor element via the        die-bonding adhesive layer (3 a).

Further, this invention relates to a semiconductor device comprising achipped work fixed onto a semiconductor element via the die-bondingadhesive (3 a) by the method of fixing a chipped work to a substrate ora chip.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an example of a sectional view of the dicing/die-bonding film(1) of the present invention.

FIG. 2 is an example of a sectional view of the other dicing/die-bondingfilm (1) of the present invention.

FIG. 3 is an example of a sectional view of the dicing/die-bonding film(2) of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, the dicing/die-bonding film of the present invention isdescribed by reference to the drawings. FIGS. 1 and 2 are sectionalviews of the dicing/die-bonding film (1) of this invention thatcomprises a pressure-sensitive adhesive layer (2) on a supporting basematerial (1) and a die-bonding adhesive layer (3) on thepressure-sensitive adhesive layer (2).

In FIG. 1, the regions (2 a, 2 b) in the pressure-sensitive adhesivelayer (2) are designed such that the releasability from the die-bondingadhesive layer (3) is in the relationship: the releasability of theinterface (A) corresponding to the work-attaching region (3 a) is higherthan the releasability of the interface (B) corresponding to the otherregion (3 b). The pressure-sensitive adhesive layer (2 a) corresponds tothe work-attaching region (3 a) in the die-bonding adhesive layer (3),and the pressure-sensitive adhesive layer (2 b) corresponds to the otherregion (3 b).

FIG. 2 shows an example wherein the part of the region (3 b) correspondsto the dicing ring-attaching region (3 b′). That is, the releasabilityof the interface (B′) between the dicing ring-attaching region (3 b′)and its corresponding pressure-sensitive adhesive layer (2 b′) isdesigned to be in the relationship: the releasability of the interface(A) is higher than the releasability of the interface (B′). In FIG. 1,the whole of the pressure-sensitive adhesive layer (2) except for thepressure-sensitive adhesive layer (2 a) is the pressure-sensitiveadhesive layer (2 b), but as shown in FIG. 2, the part of thepressure-sensitive adhesive layer (2) except for the pressure-sensitiveadhesive layer (2 a) can also be the pressure-sensitive adhesive layer(2 b).

FIG. 3 shows a sectional view of the dicing/die-bonding film (2) of thisinvention that comprises a pressure-sensitive adhesive layer (2) on asupporting base material (1) and a work-attaching region (3 a) on a partof the pressure-sensitive adhesive layer (2). The respective regions (2a, 2 b) are designed such that the adhesion of the region (2 a)corresponding to the work-attaching region (3 a) and the adhesion of theother region (2 b) in the pressure-sensitive adhesive layer (2) is inthe relationship: the adhesion of the pressure-sensitive adhesive layer(2 a) is lower than the adhesion of the pressure-sensitive adhesivelayer (2 b).

The supporting base material (1) serves as a material conferringstrength on the dicing/die-bonding film. Examples thereof includepolyolefins such as low-density polyethylene, linear polyethylene,medium-density polyethylene, high-density polyethylene,super-low-density polyethylene, a random copolymer of polypropylene, ablock copolymer of polypropylene, homopolypropylene, polybutene andpolymethyl pentene; an ethylene-vinyl acetate copolymer, ionomer resin,an ethylene/(meth)acrylic acid copolymer, an ethylene/(meth)acrylate(random, alternating) copolymer, an ethylene-butene copolymer, anethylene-hexene copolymer, polyurethane, polyesters such as polyethyleneterephthalate and polyethylene naphthalene, polycarbonate, polyimide,polyether ether ketone, polyimide, polyether imide, polyamide, aromaticpolyamide, polyphenyl sulfide, aramid (paper), glass, glass cloth,fluorine resin, polyvinyl chloride, polyvinylidene chloride, celluloseresin, silicone resin, metal (foil), paper etc.

The material of the supporting base material includes polymers such ascrosslinked resin. The plastic film may be non-stretched or may besubjected to uniaxial or biaxial stretching treatment if necessary. Theresin sheet endowed with thermal shrinkage by stretching treatment canthermally shrink the supporting base material after dicing, whereby thecontact area between the pressure-sensitive adhesive layer (2 a) and theadhesive layer (3 a) is reduced to facilitate recovery of the chippedwork.

The surface of the supporting base material can be subjected to ordinarysurface treatment for improving adhesion and maintenance of the adjacentlayer, for example chemical or physical treatment such as treatment withchromate, exposure to ozone, exposure to flames, high-voltage electricshock exposure, and treatment with ionization radiations, or coatingtreatment with a undercoat (for example, a sticky material describedlater).

The material of the supporting base material may be the same material ora suitable mixture of different materials, and if necessary a blend ofseveral materials can also be used. Further, the supporting basematerial may be provided thereon with an electroconductive deposit of 30to 500 Å in thickness composed of a metal, an alloy or oxide thereof inorder to confer antistatic performance. The supporting base material maybe composed of a single or two or more layers. When thepressure-sensitive adhesive layer (2) is radiation-curing type, asupporting base material partially transmitting radiations such as Xrays, UV rays and electron rays is used.

The thickness of the supporting base material (1) can be suitablydetermined without particular limitation, but is generally about 5 to200 μm.

The pressure-sensitive adhesive used in formation of thepressure-sensitive adhesive layer (2) is not particularly limited, butis preferably a radiation-curing pressure-sensitive adhesive easilyproviding a difference in adhesion between the pressure-sensitiveadhesive layers (2 a) and (2 b). The radiation-curing pressure-sensitiveadhesive can easily lower the adhesion by increasing the degree ofcrosslinking upon irradiation with radiations such as UW rays.Accordingly, the radiation-curing pressure-sensitive adhesive layerfitted with the work-attaching region (3 a) can be cured to easilyprovide the pressure-sensitive adhesive layer (2 a) with a significantreduction in adhesion. Because the adhesive layer (3) or (3 a) is stuckon the pressure-sensitive adhesive layer (2 a) whose adhesion wasreduced, the interface between the pressure-sensitive adhesive layer (2a) and the adhesive layer (3 a) is inherently easily separated at thepickup step. On the other hand, the region not irradiated withradiations has sufficient adhesion, and forms the pressure-sensitiveadhesive layer (2 b).

In the dicing/die-bonding film (1), the pressure-sensitive adhesivelayer (2 b) made of the uncured radiation-curing pressure-sensitiveadhesive adheres to the adhesive layer (3), thus maintaining retainingforce at the dicing step. Thus, the radiation-curing pressure-sensitiveadhesive can, with good balance between adhesion and release, supportthe die-bonding adhesive layer (3) for fixing a chipped work(semiconductor chip etc.) to an adherend (referred to as semiconductorelement) such as a substrate and a chipped work. In thedicing/die-bonding film (2), the pressure-sensitive adhesive layer (2 b)can fix a wafer ring etc.

The radiation-curing pressure-sensitive adhesive used in formation ofthe pressure-sensitive adhesive layer (2) can be used without particularlimitation insofar as it has radiation-curing functional groups such ascarbon-carbon double bonds and simultaneously shows adhesion.

Examples of the radiation-curing pressure-sensitive adhesive includeaddition-type radiation-curing pressure-sensitive adhesives comprising aradiation-curing monomer component or oligomer component compounded witha general pressure-sensitive adhesive for example the above-mentionedacrylic pressure-sensitive adhesive or rubber pressure-sensitiveadhesive. From the viewpoint of cleaning and detergency forpollutant-free electronic parts such as semiconductor wafers and glasswith ultra-pure water or an organic solvent such as alcohol, thepressure-sensitive adhesive is preferably an acrylic pressure-sensitiveadhesive based on an acrylic polymer.

The acrylic polymer is, for example, an acrylic polymer using one ormore monomer components selected from alkyl (meth)acrylates (forexample, C₁₋₃₀ alkyl, particularly C₄₋₁₈ linear or branched alkyl esterssuch as methyl ester, ethyl ester, propyl ester, isopropyl ester, butylester, isobutyl ester, s-butyl ester, t-butyl ester, pentyl ester,isopentyl ester, hexyl ester, heptyl ester, octyl ester, 2-ethyl hexylester, isooctyl ester, nonyl ester, decyl ester, isodecyl ester, undecylester, dodecyl ester, tridecyl ester, tetradecyl ester, hexadecyl ester,octadecyl ester, eicosyl ester etc.) and cycloalkyl (meth)acrylates (forexample, cyclopentyl ester, cyclohexyl ester etc.). The (meth)acrylatesrefer to acrylates and/or methacrylates, and in this meaning, (meth) isused throughout in this invention.

For the purpose of improving cohesiveness and heat resistance, theacrylic polymer may contain units corresponding to other monomercomponents copolymerizable with the above (meth)acrylates and cycloalkylesters. Such monomer components include, for example, carboxylgroup-containing monomers such as acrylic acid, methacrylic acid,carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconicacid, maleic acid, fumaric acid and crotonic acid; acid anhydridemonomers such as maleic anhydride and itaconic anhydride; hydroxylgroup-containing monomers such as 2-hydroxyethyl (meth)acrylate,2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate,6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate,10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate and(4-hydroxymethylcyclohexyl)methyl (meth)acrylate; sulfonic acidgroup-containing monomers such as styrenesulfonic acid, allylsulfonicacid, 2-(meth)acrylamide-2-methylpropanesulfonic acid,(meth)acrylamidopropanesulfonic acid and sulfopropyl (meth)acrylate,(meth)acryloyloxy naphthalene sulfonic acid;

phosphate group-containing monomers such as 2-hydroxyethylacryloylphosphate; and acrylamide, acrylonitrile etc. One or more of thesecopolymerizable monomer components can be used. The amount of thesecopolymerizable monomers is preferably 40% or less by weight based onthe total monomer components.

If necessary, the acrylic polymers can contain multifunctional monomersto be crosslinked as copolymerizable monomer components. Themultifunctional monomers include, for example, hexanedioldi(meth)acrylate, (poly)ethylene glycol di(meth)acrylate,(poly)propylene glycol di(meth)acrylate, neopentyl glycoldi(meth)acrylate, pentaerythritol di(meth)acrylate, trimethylol propanetri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritolhexa(meth)acrylate, epoxy (meth)acrylate, polyester (meth)acrylate,urethane (meth)acrylate etc. One or more of these multifunctionalmonomers can be used. From the viewpoint of adhesion properties etc.,the amount of the multifunctional monomers is preferably 30% or less byweight based on the total monomer components.

The acrylic polymer is obtained by subjecting a single monomer or amixture of two or more monomers to polymerization. This polymerizationcan be carried out in any systems of solution polymerization, emulsionpolymerization, bulk polymerization and suspension polymerization. Fromthe viewpoint of preventing pollution of a clean adherend, the contentof low-molecular substances in the acrylic polymer is preferably lower.In this respect, the number-average molecular weight of the acrylicpolymer is preferably 300,000 or more, more preferably about 400,000 to3,000,000.

The pressure-sensitive adhesive can suitably use an externalcrosslinking agent for increasing the number-average molecular weight ofthe acrylic polymer etc. as the base polymer. A specific means of anexternal crosslinking method includes a method of reacting monomers byadding a crosslinking agent such as polyisocyanate compound, epoxycompound and aziridine compound, melamine-based crosslinking agent. Whenthe external crosslinking agent is used, the amount of the crosslinkingagent used is suitably determined according to balancing with the basepolymer to be crosslinked and the use of the pressure-sensitiveadhesive. Generally, the external crosslinking agent is compounded in anamount of preferably 5 parts or less by weight, more preferably 0.1 to 5parts by weight, based on 100 parts by weight of the base polymer. Ifnecessary, the pressure-sensitive adhesive may include various kinds ofconventional additives such as tackifier, antioxidants etc.

The radiation-curing monomer components blended include, for example,urethane oligomers, urethane (meth)acrylate, trimethylol propanetri(meth)acrylate, tetramethylol methane tetra(meth)acrylate,pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate,dipentaerythritol monohydroxypenta(meth)acrylate, dipentaerythritolhexa(meth)acrylate, 1,4-butanediol di(meth)acrylate etc. Theradiation-curing oligomer components include various oligomers such asthose based on urethane, polyether, polyester, polycarbonate andpolybutene, and the molecular weight thereof is preferably in the rangeof about 100 to 30000. Depending on the type of the pressure-sensitiveadhesive layer, the amount of the radiation-curing monomer componentsand oligomer components blended can be suitably determined so as tolower the adhesion of the pressure-sensitive adhesive layer. Generally,the amount thereof is for example 5 to 500 parts by weight, preferably40 to 150 parts by weight, based on 100 parts by weight of the basepolymer such as the acrylic polymer constituting the pressure-sensitiveadhesive.

The radiation-curing pressure-sensitive adhesive includes not only theabove-described addition-type radiation curing pressure-sensitiveadhesives, but also internal-type radiation-curing pressure-sensitiveadhesives using a base polymer having carbon-carbon double bonds in sidechains or main chain of the polymer or at the end of the main chain. Theinternal-type radiation-curing pressure-sensitive adhesive is preferablebecause it does not requires incorporation of low-molecular componentssuch as oligomer components or does not contain a large amount ofoligomer components, thus enabling formation of a pressure-sensitiveadhesive layer having a stable layer structure without movement withtime of the oligomer components etc. in the pressure-sensitive adhesive.

The base polymer having carbon-carbon double bonds can be used withoutparticular limitation insofar as it has carbon-carbon double bonds andsimultaneously has adhesion. The base polymer preferably has an acrylicpolymer as a fundamental skeleton. As the fundamental skeleton of theacrylic polymer, mention is made of the above-exemplified acrylicpolymer.

The method of introducing carbon-carbon double bonds into the acrylicpolymer is not particularly limited and various methods can be used, butit is easy in molecular design to introduce carbon-carbon double bondsinto side chains of the polymer. For example, mention is made of amethod in which a monomer having a functional group is copolymerizedwith the acrylic polymer, and then a compound having carbon-carbondouble bonds and a functional group capable of reacting with the abovefunctional group is subjected, while the radiation curing properties ofthe carbon-carbon double bonds are maintained, to condensation oraddition reaction with the copolymer.

Combinations of these functional groups include, for example, acarboxylic acid group and an epoxy group, a carboxylic acid group and anaziridyl group, and a hydroxyl group and an isocyanate group. Amongthose combinations of functional groups, a combination of a hydroxylgroup and an isocyanate group is preferable for easy monitoring of thereaction. Further, if a combination of such functional groups is acombination forming the acrylic polymer having carbon-carbon doublebonds, the functional groups may be present in either the acrylicpolymer or the above compound, and it is preferable in the abovepreferable combination that the acrylic polymer has a hydroxyl group,and the above compound has an isocyanate group. In this case, theisocyanate compound having carbon-carbon double bonds includes, forexample, methacryloyl isocyanate, 2-methacryloyl oxyethyl isocyanate,m-isopropenyl-α,α-dimethylbenzyl isocyanate etc. As the acrylic polymer,use is made of a polymer prepared by copolymerizing theabove-exemplified hydroxyl group-containing monomer or an ether compoundsuch as 2-hydroxy ethyl vinyl ether, 4-hydroxy butyl vinyl ether ordiethylene glycol monovinyl ether.

As the internal-type radiation-curing pressure-sensitive adhesive, thebase polymer having carbon-carbon double bonds (particularly the acrylicpolymer) can be singly used. The radiation-curing monomer components andoligomer components can also be compounded to such a degree that thecharacteristics are not deteriorated. The amount of the radiation-curingoligomer components is usually in the range of 0 to 30 parts by weight,preferably 0 to 10 parts by weight, based on 100 parts by weight of thebase polymer.

For curing with UV rays etc., the radiation-curing pressure-sensitiveadhesive is blended with a photopolymerization initiator. Thephotopolymerization initiator includes, for example, α-ketol compoundssuch as

-   -   4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)ketone,    -   α-hydroxy-α,α′-dimethyl acetophenone,    -   2-methyl-2-hydroxypropiophenone and 1-hydroxycyclohexyl phenyl        ketone; acetophenone compounds such as methoxy acetophenone,        2,2-dimethoxy-2-phenyl acetophenone, 2,2-diethoxy acetophenone        and 2-methyl-1-[4-(methylthio)-phenyl]-2-morpholinopropane-1;    -   benzoin ether compounds such as benzoin ethyl ether, benzoin        isopropyl ether and anisoin methyl ether; ketal compounds such        as benzyl dimethyl ketal; aromatic sulfonyl chloride compounds        such as 2-naphthalene sulfonyl chloride; optically active oxime        compounds such as    -   1-phenone-1,1-propanedione-2-(o-ethoxycarbonyl)oxime;    -   benzophenone compounds such as benzophenone, benzoylbenzoic acid        and 3,3′-dimethyl-4-methoxy benzophenone; thioxanthone compounds        such as thioxanthone, 2-chlorothioxanthone, 2-methyl        thioxanthone, 2,4-dimethyl thioxanthone, isopropyl thioxanthone,        2,4-dichlorothioxanthone, 2,4-diethyl thioxanthone and        2,4-diisopropyl thioxanthone; camphor quinone; halogenated        ketones; acyl phosphinoxides; and acyl phosphonates. The amount        of the photopolymerization initiator blended is for example 0.05        to 20 parts by weight based on 100 parts by weight of the base        polymer such as acrylic polymer constituting the        pressure-sensitive adhesive.

The radiation-curing pressure-sensitive adhesive includepressure-sensitive adhesive disclosed in JP-A 60-196956, for examplerubber-based pressure-sensitive adhesive and acrylic pressure-sensitiveadhesive containing an addition-polymerizable compound having two ormore unsaturated bonds or a photopolymerizable compound such as alkoxysilane having an epoxy group and a photopolymerizable initiator such asa carbonyl compound, organic sulfur compound, peroxide, amine, or oniumsalt-based compound.

If necessary, the radiation-curing pressure-sensitive adhesive layer (2)can also contain a compound to be colored by irradiation withradiations. By incorporating the compound colored by irradiation withradiations into the radiation-curing pressure-sensitive adhesive (2),only a region irradiated with radiations can be colored. That is, thepressure-sensitive adhesive layer (2 a) corresponding to thework-attaching region (3 a) can be colored. Accordingly, whether thepressure-sensitive adhesive layer (2) has been irradiated withradiations can be immediately judged with the naked eye, and thework-attaching region (3 a) can be easily recognized to facilitateattachment to a work. Further, when the resulting semiconductor elementis detected by an optical sensor etc., the detection accuracy isimproved, thus preventing erroneous working in pickup of thesemiconductor element.

The compounds to be colored by irradiation with radiations are colorlessor light-colored before irradiation with radiations, but are colored byirradiation with radiations. Preferable examples of such compoundsinclude leuco dyes. The leuco dyes used are preferably conventional dyesbased on triphenyl methane, fluoran, phenothiazine, auramine andspiropyran. Specifically, mention is made of3-[N-(p-tolylamino)]-7-anilinofluoran,3-[N-(p-tolyl)-N-methylamino]-7-anilinofluoran,3-[N-(p-tolyl)-N-ethylamino]-7-anilinofluoran,3-diethylamino-6-methyl-7-anilinofluoran, crystal violet lactone,4,4′,4″-trisdimethylaminotriphenyl methanol, and4,4′,4″-trisdimethylaminotriphenyl methane, etc.

Developers used preferably with these leuco dyes include electronacceptors, for example conventionally used initial polymers ofphenol-formalin resin, aromatic carboxylic acid derivatives, activatedclay etc., and can be used in combination with various coloring agentsfor changing color tone.

The compound to be colored with irradiation with radiations may be firstdissolved in an organic solvent etc. and then incorporated into theradiation-curing pressure-sensitive adhesive, or may be first pulverizedfinely and then incorporated into the pressure-sensitive adhesive. Theratio of this compound used is 10% or less by weight, preferably 0.01 to10% by weight, more preferably 0.5 to 5% by weight, based on thepressure-sensitive adhesive layer (2). When the ratio of the compound ishigher than 10% by weight, too much radiation applied to thepressure-sensitive adhesive layer (2) is adsorbed into this compound,and therefore the pressure-sensitive adhesive layer (2 a) is hardlycured, thus failing to lower adhesion sufficiently. For sufficientcoloration, on the other hand, the ratio of the compound is preferably0.01% or more by weight.

The pressure-sensitive adhesive layer (2) is arranged such that theadhesion of the pressure-sensitive adhesive layer (2 a) is lower thanthe adhesion of the pressure-sensitive adhesive layer (2 b). In thedicing/die-bonding film (1), the adhesion to the die-bonding adhesivelayer (3) is determined such that the releasability of the interface (A)is higher than the releasability of the interface (B). In thedicing/die-bonding film (2), the adhesion of the pressure-sensitiveadhesive layer (2 a) to an SUS304 plate (#2000 polishing) as an adherendis lower than the adhesion of the pressure-sensitive adhesive layer (2b) to the plate.

In the case where the pressure-sensitive adhesive layer (2) is formedfrom a radiation-curing pressure-sensitive adhesive, mention is made ofa method wherein the radiation-curing pressure-sensitive adhesive layer(2) is formed on the supporting base material (1), a regioncorresponding to the work-attaching region (3 a) is cured by partialirradiation with radiations, to form the pressure-sensitive adhesivelayer (2 a). The partial irradiation with radiations can be carried outvia a photomask having a pattern corresponding to the region (3 b etc.)other than the work-attaching region (3 a). Mention is also made of amethod of curing the pressure-sensitive adhesive layer by spotirradiation with UW rays. Formation of the radiation-curingpressure-sensitive adhesive layer (2) can be carried out by transferringthe layer arranged on a separator to the supporting base material (1).The radiation-curing pressure-sensitive adhesive layer (2) arranged onthe separator may be subjected to partial curing with radiations.

Alternatively, when the pressure-sensitive adhesive layer (2) is formedfrom a radiation-curing pressure-sensitive adhesive, use can be made ofa method wherein the supporting base material (1), at least one side ofwhich is light-shielded except for the whole or a part of a regioncorresponding to the work-attaching region (3 a), is provided with theradiation-curing pressure-sensitive adhesive layer (2) and then cured inthe region corresponding to the work-attaching region (3 a) to form thepressure-sensitive adhesive layer (2 a) whose adhesion is lowered.Printing or depositing a material capable of serving as a photomask onthe supporting film can produce the light-shielding material. Accordingto such production method, the dicing/die-bonding film of this inventioncan be efficiently produced.

When curing inhibition by oxygen occurs during irradiation withradiations, the surface of the radiation-curing pressure-sensitiveadhesive layer (2) is preferably shielded from oxygen (air) by somemethods. Such methods involve covering the surface of thepressure-sensitive adhesive layer (2) with a separator or irradiatingwith radiations such as UV rays etc. in a nitrogen atmosphere.

The thickness of the pressure-sensitive adhesive layer (2) is notparticularly limited, but is preferably about 1 to 50 μm from theviewpoint of preventing the cut surface of a chip from being broken andsimultaneously retaining the adhesive layer. The thickness is morepreferably 2 to 30 μm, still more preferably 5 to 25 μm.

When a work (semiconductor wafer etc.) contact-bonded onto thedie-bonding adhesive layer (3) is diced into chips, the adhesive layer(3) adheres to and supports the work, and when the chipped work formedinto cut fragment (semiconductor chip etc.) is to be mounted, theadhesive layer works for fixing the chipped work to a semiconductorelement (substrate, chip etc.). It is particularly important that thedie-bonding adhesive layer (3) has such adhesion as not to scatter cutfragments during dicing of the work. In the dicing/die-bonding film (2),the die-bonding adhesive layer (3) is arranged in the previously formedwork-attaching region (3 a).

The die-bonding adhesive layer (3) can be formed from a usual dieadhesive. The die adhesive is preferably an adhesive that can be formedinto a sheet. Preferable examples of the die adhesive include dieadhesives made of thermoplastic or thermosetting resins. The dieadhesives can be used alone or more in combination thereof. Thedie-bonding adhesive layer is preferably a layer that can stick to awork such as a semiconductor wafer or to a dicing ring at 70° C. orless. The die-bonding adhesive layer is more preferably a layer that canstick at ordinary temperatures.

The thermoplastic resin used as the die adhesive (thermoplastic dieadhesive) includes, for example, saturated polyester resin,thermoplastic polyurethane-based resin, amide-based resin (nylon-basedresin), imide-based resin etc. The thermosetting resin (thermosettingdie adhesive) includes, for example, epoxy resin, unsaturatedpolyester-based resin, thermosetting acrylic resin, phenol resin etc.The thermosetting resin is preferably a thermosetting resin in B-stage,which was desolvated and formed into a sheet. A mixture in B-stage ofthe thermosetting resin and thermoplastic resin can also be used. Inthis invention, resins for examples those having a high glass transitiontemperature based on silicone, rubber, urethane, imide and acryl canalso be used as the die adhesive.

The die-bonding adhesive layer (3) may have a two- or more multi-layerstructure by suitably combining thermoplastic resins different in glasstransition temperature or thermosetting resins different inthermosetting temperature. Because water for cutting is used in the stepof dicing the work (semiconductor wafer etc.), the die-bonding adhesivelayer (3) adsorbs moisture to attain a water content higher than in anordinary state. When the adhesive layer (3) having such a high watercontent is allowed to adhere to a substrate etc., water vapor may beretained in the interface of the adhesive at the after-cure stage tocause lifting. Accordingly, the die-bonding adhesive is constituted suchthat a film highly adsorbing moisture is sandwiched between the dieadhesives, whereby water vapor is diffused through the film at theafter-cure stage, to overcome the problem. Accordingly, the die-bondingadhesive layer (3) may be composed of a multi-layer structure having anadhesive layer, a film and an adhesive layer laminated in this order.

Though not particularly limited, the thickness of the die-bondingadhesive layer (3) is for example about 5 to 100 μm, preferably about 10to 50 μm.

The dicing/die-bonding films (1) and (2) comprising thepressure-sensitive adhesive layer (2) on the supporting base material(1) and the die-bonding adhesive layer (3) on the pressure-sensitiveadhesive layer (2) are obtained in this manner.

The dicing/die-bonding films (1) and (2) can be endowed with antistaticperformance for the purpose of preventing generation of staticelectricity upon sticking or release, or breakage of circuits by works(semiconductor wafer etc.) electrified with such static electricity.Antistatic performance can be given in a suitable system, for example byadding an antistatic agent or an electroconductive material to thesupporting base material (1), the pressure-sensitive adhesive layer (2)or the adhesive layer (3) or by providing the supporting base material(1) with an electrostatic layer made of a charge-transferring complex ora metallic film. This system is preferably a system not generatingcontaminating ions that may denature semiconductor wafers. Theelectroconductive material (electroconductive filers) incorporated forthe purpose of conferring electrical conductivity, thermal conductivityetc. includes spherical, needle or flaky metal powders of silver,aluminum, gold, copper, nickel, electroconductive alloys etc., metaloxides such as alumina, amorphous carbon black, graphite etc.

In the dicing/die-bonding film (1), the adhesion of thepressure-sensitive adhesive layer (2) to the die-bonding adhesive layer(3) is designed such that the adhesion of the pressure-sensitiveadhesive layer (2 a) is lower than the adhesion of thepressure-sensitive adhesive layer (2 b). On the basis of the adhesion(900 peel value, peel rate 300 mm/min.) at ordinary temperature (23°C.), the adhesion of the pressure-sensitive adhesive layer (2 a) ispreferably not higher than 0.5 N/20 mm, more preferably 0.01 to 0.42N/20 mm, still more preferably 0.01 to 0.35 N/20 mm from the viewpointof retention of a wafer or recovery of formed chips. On the other hand,the adhesion of the pressure-sensitive adhesive layer (2 b) ispreferably about 0.5 to 20 N/20 mm. Even if the pressure-sensitiveadhesive layer (2 a) has low peel adhesion, the adhesion of thepressure-sensitive adhesive layer (2 b) can prevent chips from beingscattered, and can demonstrate sufficient retention for processing ofwafers.

In the dicing/die-bonding film (2), the region (2 a) corresponding tothe work-attaching region (3 a) and the other region (2 b) in thepressure-sensitive adhesive layer (2) are designed such that theadhesion of the pressure-sensitive adhesive layer (2 a) is lower thanthe adhesion of the pressure-sensitive adhesive layer (2 b). Theadhesion of the pressure-sensitive adhesive layer (2 a) to thework-attaching region (3 a) (under the same conditions as describedabove) is not higher than 0.5 N/20 mm, more preferably 0.01 to 0.42 N/20mm, and still more preferably 0.01 to 0.35 N/20 mm.

In the dicing/die-bonding films (1) and (2), the adhesion of thework-attaching region (3 a) to the work and to the pressure-sensitiveadhesive layer (2 a) is desired preferably such that the adhesion to thework is higher than the adhesion to the pressure-sensitive adhesivelayer (2 a). The adhesion to the work is regulated suitably depending onthe type of the work.

As described above, the adhesion of the work-attaching region (3 a) tothe pressure-sensitive adhesive layer (2 a) (under the same conditionsas described above) is not higher than 0.5 N/20 mm, more preferably 0.01to 0.42 N/20 mm, and still more preferably 0.01 to 0.35 N/20 mm. On theother hand, the adhesion of the work-attaching region (3 a) to the work(under the same conditions as described above) is not higher than 10 to50 N/20 mm, more preferably 10 to 30 N/20 mm, from the viewpoint ofpickup and reliability at the time of dicing, pickup, and die-bonding.

When the region (3 b) other than the work-attaching region (3 a) is usedas the dicing ring-attaching region (3 b′) in the dicing/die-bondingfilm (1), the adhesion of the dicing ring-attaching region (3 b′) in thedie-bonding adhesive layer (3) to the work and to the pressure-sensitiveadhesive layer (2 b′) is designed preferably such that the adhesion tothe dicing ring is lower than the adhesion to the pressure-sensitiveadhesive layer (2 b′). The adhesion to the dicing ring is regulatedsuitably depending on the type of the dicing ring.

As described above, the adhesion of the die-bonding adhesive layer (3)to the pressure-sensitive adhesive layer (2 b′) (under the sameconditions as described above) is preferably about 0.5 to 20 N/20 mm. Onthe other hand, the adhesion of the die-bonding adhesive layer (3) tothe dicing ring is preferably 0.3 to 5 N/20 mm, more preferably 0.5 to 5N/20 mm, from the view point of workability at the time of dicing anddie-bonding.

In the dicing/die-bonding films (1) and (2), the die-bonding adhesivelayers (3) and (3 a) may be protected with a separator (not shown indrawings). That is, a separator may be arbitrarily arranged. Theseparator functions as a protecting material protecting the die-bondingadhesive layers (3) and (3 a). Further, the separator can also be usedas a supporting base material for transferring the die-bonding adhesives(3) and (3 a) to the pressure-sensitive adhesive layer (2). Theseparator is removed just before a work is stuck on the die-bondingadhesive layer (3) or (3 a) in the dicing/die-bonding film (1) or (2).The separator includes a polyethylene or polypropylene film or a plasticfilm and paper coated with a releasing agent such as fluorine releasingagent or a long chain alkyl acrylate releasing agent.

After the separator arranged arbitrarily on the adhesive layer (3) or (3a) is removed, the dicing/die-bonding film (1) or (2) of this inventionis used in the following manner. That is, a work is pressed to thedie-bonding adhesive layer (3 a) in the dicing/die-bonding film (1) or(2), and the work is adhesive-bonded to the adhesive layer (3 a). Thispressing is carried out in a usual manner. The work used in thisinvention is preferably a semiconductor wafer. Then, the work is dicedinto chips. The work includes, for example, a semiconductor wafer, amulti-layer substrate, a simultaneously sealed module etc. The work usedin this invention is preferably a semiconductor wafer. By dicing, thework having the adhesive layer (3) is formed into chipped works(semiconductor chips etc.) by suitable means using a rotating circulartooth.

Then, the chipped work together with the die-bonding adhesive layer (3a) is released from the pressure-sensitive adhesive layer (2 a). Thechipped work thus picked up is adhesive-bonded via the die-bondingadhesive layer (3 a) to a semiconductor element as an adherend. Thesemiconductor element includes a lead frame, a TAB film, a substrate ora separately prepared chipped work. For example, the adherend may be adeformed adherend to be easily deformed, or a hardly deformablenon-deformed adherent (semiconductor wafer etc.). The adherend ispreferably a semiconductor wafer. When the adhesive layer (3) or (3 a)is thermosetting, the work is adhesive-bonded to an adherend bythermosetting, to improve heat resistance. For example, the chipped workadhesive-bonded to a substrate via the adhesive layers (3 a) can besubjected to a reflow process.

EXAMPLES

Hereinafter, this invention is described in more detail by reference tothe Examples. In the following description, “parts” refers to parts byweight. For irradiation with ultraviolet rays, an ultraviolet (UV)irradiation unit (NEL UM-110 (Nitto Seiki Co., Ltd.) was used.

Production Example Preparation of a Die-Bonding Adhesive Layer

The components shown in Table 1 below, that is, epoxy resin, phenolresin, acrylic rubber, silica and a curing accelerator were compoundedin the ratios shown in the table to prepare compositions for die-bondingadhesives (A) to (C), and each composition was mixed with and dissolvedin toluene. The mixed solution was applied onto a polyester film(separator) treated with a releasing agent. Then, the polyester filmcoated with the mixed solution was dried at 120° C. to remove thetoluene, whereby each of the die-bonding adhesive layers A to C of 20 μmin thickness in the B-stage on the polyester film were obtained. TABLE 1Die-bonding adhesive (parts by weight) Compositions A B C Epoxy resin(a1) 24.9 24.9 15.5 Epoxy resin (a2) 24.9 24.9 15.5 Phenol resin 29.229.2 18 Acrylic rubber 20 20 50 Silica 0 100 100 Curing accelerator 1 11

In Table 1,

-   -   <Epoxy resin (a1)> is bisphenol A type epoxy resin (epoxy        equivalent, 186 g/eq.; viscosity, 10 Pa.s/25° C.),    -   <Epoxy resin (a2)> is triphenol methane type epoxy resin (epoxy        equivalent, 170 g/eq.; softening point, 80° C.; viscosity, 0.08        Pa.s/150° C.),    -   <Phenol resin> is novolak type phenol resin (hydroxyl group        equivalent, 104 g/eq.; softening point, 80° C.; viscosity, 0.1        Pa.s/ 150° C.),    -   <Acrylic rubber> (Mooney viscosity: 50),    -   <Spherical silica> Average particle diameter, 1 μm; maximum        particle diameter, 10 μm, and    -   <Curing accelerator> is triphenylphosphine.

Example 1 Preparation of a Radiation-Curing Acrylic Pressure-SensitiveAdhesive

70 parts of butyl acrylate, 30 parts of ethyl acrylate and 5 parts ofacrylic acid were copolymerized in ethyl acetate in a usual manner togive a solution containing an acrylic polymer at a concentration of 30%by weight having a weight-average molecular weight of 800,000. 20 partsof dipentaerythritol monohydroxy pentaacrylate as a photopolymerizablecompound and 1 part of α-hydroxy cyclohexyl phenyl ketone as aphotopolymerization initiator were compounded with the acrylic polymersolution. The mixture was dissolved uniformly in toluene to prepare asolution containing a radiation-curing acrylic pressure-sensitiveadhesive at a concentration of 25% by weight.

(Preparation of a dicing/Die-Bonding Film

The above radiation-curing acrylic pressure-sensitive adhesive solutionwas applied onto a polyethylene film of 60 μm in thickness as thesupporting base material and dried to form a pressure-sensitive adhesivelayer of 20 μm in thickness. Hereinafter, the resulting product isreferred to as pressure-sensitive adhesive film (A). Only awafer-attaching region of the pressure-sensitive adhesive layer in thepressure-sensitive adhesive film (A) was irradiated with UV rays in atotal dose of 500 mJ/cm² to give a film having the pressure-sensitiveadhesive layer whose wafer-attaching region had been cured by UW rays.Then, the above die-bonding adhesive layer (A) was transferred onto thepressure-sensitive adhesive layer of the pressure-sensitive adhesivefilm (A), to give a dicing/die-bonding film.

Example 2

A dicing/die-bonding film was prepared in the same manner as in Example1 except that the die-bonding adhesive (B) was used in place of thedie-bonding adhesive (A) in Example 1.

Example 3

(Preparation of a Radiation-Curing Acrylic Pressure-Sensitive Adhesive)

A composition consisting of 50 parts of ethyl acrylate, 50 parts ofbutyl acrylate and 16 parts of 2-hydroxyethyl acrylate was copolymerizedin a toluene solvent, to give a solution containing an acrylic polymerat a concentration of 35% by weight having a weight-average molecularweight of 500,000. Then, 20 parts of 2-methacryloyloxyethyl isocyanatewas subjected to addition polymerization with the acrylic polymersolution thereby introducing carbon-carbon double bonds intointramolecular side chains of the polymer. To 100 parts by weight(solids content) of this polymer were added 1 part by weight of apolyisocyanate-based crosslinking agent and 3 parts of anacetophenone-based photopolymerization initiator. These were dissolveduniformly in toluene to prepare a solution containing a radiation-curingacrylic pressure-sensitive adhesive at a concentration of 23% by weight.

(Preparation of a Dicing/Die-Bonding Film)

The above radiation-curing acrylic pressure-sensitive adhesive solutionwas applied onto a polyethylene film of 80 μm in thickness as thesupporting base material and dried to form a pressure-sensitive adhesivelayer of 5 μm in thickness. Hereinafter, the resulting product isreferred to as pressure-sensitive adhesive film (B). Only awafer-attaching region of the pressure-sensitive adhesive layer in thepressure-sensitive adhesive film (B) was irradiated with 500 mJ/cm² UVrays to give a film having the pressure-sensitive adhesive layer whosewafer-attaching region had been cured by UV rays. Then, the abovedie-bonding adhesive layer (B) was transferred onto thepressure-sensitive adhesive layer of the pressure-sensitive adhesivefilm (B), to give a dicing/die-bonding film.

Example 4

A dicing/die-bonding film was prepared in the same manner as in Example3 except that the die-bonding adhesive layer (C) was used in place ofthe die-bonding adhesive (B) in Example 3.

Example 5

A dicing/die-bonding film was prepared in the same manner as in Example3 except that the die-bonding adhesive layer (A) was used in place ofthe die-bonding adhesive (B) in Example 3.

Example 6

Only a wafer-attaching region of the pressure-sensitive adhesive layerin the pressure-sensitive adhesive film (A) obtained in Example 1 wasirradiated with UV rays in a total dose of 500 mJ/cm² to give a filmhaving the pressure-sensitive adhesive layer whose wafer-attachingregion had been cured by UV rays. Then, the above die-bonding adhesivelayer (A) was transferred onto the wafer-attaching region of thepressure-sensitive adhesive layer in the pressure-sensitive adhesivefilm (A), to give a dicing/die-bonding film.

Example 7

Only a wafer-attaching region of the pressure-sensitive adhesive layerin the pressure-sensitive adhesive film (B) obtained in Example 3 wasirradiated with UV rays in a total dose of 500 mJ/cm² to give a filmhaving the pressure-sensitive adhesive layer whose wafer-attachingregion had been cured by UV rays. Then, the above die-bonding adhesivelayer (C) was transferred onto the wafer-attaching region of thepressure-sensitive adhesive layer in the pressure-sensitive adhesivefilm (B), to give a dicing/die-bonding film.

Comparative Example 1

A dicing/die-bonding film was prepared in the same manner as in Example1 except that the pressure-sensitive adhesive layer in thepressure-sensitive adhesive film (A) was not irradiated with UV rays.

Comparative Example 2

A dicing/die-bonding film was prepared in the same manner as in Example1 except that the pressure-sensitive adhesive layer on the tpressure-sensitive adhesive film (A) was not irradiated with UV rays,and also that the die-bonding adhesive layer (A) after being transferredonto the pressure-sensitive adhesive layer was irradiated with 500mJ/cm² UV rays.

With respect to the dicing/die-bonding films obtained in the Examplesand Comparative Examples, the pressure-sensitive adhesive films and thedie-bonding adhesive layers used in the respective examples weremeasured for their adhesion in the following manner. The results areshown in Table 2.

(1) Measurement of the Adhesion Between the Die-Bonding Adhesive Layerand the Pressure-Sensitive Adhesive Film (Pressure-Sensitive AdhesiveLayer)

(Wafer-Attaching Region)

The pressure-sensitive adhesive film used in each example was irradiatedin the side of the supporting base material with UV rays (500 mJ/cm²)and cut into rectangular strips of 10 mm in width. Separately, thedie-bonding adhesive layer used in each example was stuck onto a 6-inchsilicon wafer (ground surface #2000) placed on a hot plate at 40° C.Thereafter, the pressure-sensitive adhesive film (10 mm in width) wasstuck onto the die-bonding adhesive layer at room temperature (23° C.)and left for 30 minutes in a room-temperature atmosphere, and theadhesion of the pressure-sensitive adhesive film when peeled off at apeel angle of 90° in a thermostat chamber at 23° C. was measured (stressrate of the pressure-sensitive adhesive film, 300 mm/min.). However, thepressure-sensitive adhesive film used in Comparative Example 1 wasmeasured for adhesion without irradiation with UV rays. Thepressure-sensitive adhesive film used in Comparative Example 2 wasirradiated with UV rays after attachment to the die-bonding adhesivelayer.

(Region Other Than the Wafer-Attaching Region)

The pressure-sensitive adhesive film used in each of the Examples andComparative Examples was cut into rectangular strips of 10 mm in width.Separately, the die-bonding adhesive layer used in each of the Exampleand Comparative Examples was stuck onto a 6-inch silicon wafer (groundsurface #2000) placed on a hot plate at 40° C. Thereafter, thepressure-sensitive adhesive film (10 mm in width) was stuck onto thedie-bonding adhesive layer at room temperature (23° C.) and left for 30minutes in a room-temperature atmosphere, and the adhesion of thepressure-sensitive adhesive film when peeled off at a peel angle of 900in a thermostat chamber at 23° C. was measured (stress rate of thepressure-sensitive adhesive film, 300 mm/min.).

(2) Measurement of the Adhesion of the Die-Bonding Adhesive Layer to aDicing Ring and a Wafer

The region, on which a wafer was not stuck, of the dicing/die-bondingfilm obtained in each of the Examples and Comparative Examples wasirradiated in the side of the supporting base material with UV rays (500mJ/cm²) and then cut into rectangular strips of 10 mm in width. Thedicing/die-bonding film (10 mm in width) was stuck onto a dicing ring(2-6-1 (Disco)) and a wafer (ground surface #2000) at 23° C. (roomtemperature) and then left in a room-temperature atmosphere for 30minutes, and the adhesion of the pressure-sensitive adhesive film whenpeeled off at a peel angle of 90° in a thermostat chamber at 23° C. wasmeasured (stress rate of the dicing/die-bonding film, 300 mm/min.).

(3) Measurement of the Adhesion of the Pressure-Sensitive Adhesive Filmto an SUS304 Plate (#2000 Polishing)

(Wafer-Attaching Region)

Each of the pressure-sensitive adhesive films A and B was irradiated inthe side of the supporting base material with UV rays (500 mJ/cm²) andthen cut into rectangular strips of 10 mm in width. Thereafter, thepressure-sensitive adhesive film (100 mm width) was stuck onto an SUS304plate (#2000 polishing) at room temperature (23° C.) and left for 30minutes in a room-temperature atmosphere, and the adhesion of thepressure-sensitive adhesive film when peeled off at a peel angle of 90°in a thermostat chamber at 23° C. was measured (stress rate of thepressure-sensitive adhesive film, 300 mm/min.).

(Region Other than the Wafer-Attaching Region)

Each of the pressure-sensitive adhesive films A and B was cut intorectangular strips of 10 mm in thickness. Thereafter, thepressure-sensitive adhesive film (10 mm) was stuck onto an SUS304 plate(#2000 polishing) at room temperature (23° C.) and left for 30 minutesin a room-temperature atmosphere, and the adhesion of thepressure-sensitive adhesive film when peeled off at a peel angle of 90°in a thermostat chamber at 23° C. was measured (stress rate of thepressure-sensitive adhesive film, 300 mm/min.).

The dicing/die-bonding films in Examples 1 to 7 and Comparative Example1 and 2 were evaluated for their performance in actualdicing/die-bonding of semiconductor wafers in the following manner. Theresults are shown in Table 2.

<Chip Scattering during Dicing>

A mirror wafer of 0.15 mm in thickness with a circuit pattern formedthereon, obtained by grinding the back of a semiconductor wafer having adiameter of 8 inches, was used. The separator was released from thedicing/die-bonding film, and the mirror wafer was contact-bonded bypressing a roller at 40° C. to the exposed adhesive layer and thensubjected to full-dicing into 1×1 mm square chips. Whether the chipscattering during dicing was examined. In this procedure, none of thedicing/die-bonding films in the Examples and Comparative Examples causedfailure such as chips scattering during dicing.

<Pickup>

Full-dicing was carried out in the same manner as described above exceptthat the size of the square chips was changed into 5×5 mm, 10×10 mm, and15×15 mm respectively. Thereafter, the silicon chips (chipped wafer)were picked up in a system for raising the side of the supporting basematerial by a needle. “◯” was given to successful pickup, and “x” wasgiven to unsuccessful pickup.

(Dicing Conditions)

Dicing unit: DFD-651 manufactured by Disco.

Dicing rate: 80 mm/sec.

Dicing blade: 2050HECC manufactured by Disco.

Number of rotation: 40,000 mm

Cut depth: 20 μm

Cut system: Full cut/mode A

Chip size: arbitrary (1×1 mm to 15×15 mm square)

(Wafer Grinding Conditions)

Grinding unit: DFG-840 manufactured by Disco.

Wafer: 6-inch diameter (grinding of the back from 0.6 mm to 0.15 μm)

Wafer-attaching unit: DR-850011 (Nitto Seiki Co., Ltd.)

(Expanding Conditions)

Dicing ring: 2-6-1 (Internal diameter 19.5 cm, manufactured by Disco)

Drawdown: 5 mm

Die bonder: CPS-100 (NEC Kikai) TABLE 2 Compara- Compara- tive tiveExam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- ple 1 ple 2 ple 3ple 4 ple 5 ple 6 ple 7 ple 1 ple 2 Die-bonding Type A B B C A A C A Aadhesive Thickness (μm) 20 20 20 20 20 20 20 20 20 Pressure-sensi- TypeA A B B B A B A A tive adhesive Thickness (μm) 80 80 85 85 85 80 85 8080 film Irradiation of Before present present present present presentpresent present absent absent the attachment of wafer-attach- wafer ingregion After absent absent absent absent absent absent absent absentpresent with UV rays attachment of wafer (1) Adhesion Wafer-attach- 0.150.08 0.09 0.12 0.26 0.15 0.12 5.5 25 between the ing region die-bondingOther region 3.3 2.35 3.8 4.8 3.55 — — 5.5 3.3 adhesive than layer andthe wafer-attach- pressure-sens- ing region tive adhesive film N/10 mm(2) Adhesion Wafer 17.5 16.2 16.2 21.5 17.5 17.5 21.5 17.5 17.5 of theDicing ring 1.25 1.1 1.1 1.9 1.25 — — 1.25 1.25 die-bonding adhesivelayer (N/10 mm) (3) Adhesion Wafer-attach- — — — — — 0.05 0.09 — — ofthe ing region pressure-sens- Other region — — — — — 8.5 5.7 — — tiveadhesive than film to wafer-attach- SUS304 ing region (N/10 mm) ChipDicing/1 × 1 none none none none none none none none none scattering mmsquare Pickup Dicing/5 × 5 ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ X mm square Dicing/10 × 10 ◯◯ ◯ ◯ ◯ ◯ ◯ X X mm square Dicing/15 × 15 ◯ ◯ ◯ ◯ ◯ ◯ ◯ X X mm square

None of the dicing/die-bonding films in the Examples and the ComparativeExamples showed failure in dicing. All chips could be well picked upfrom the dicing/die-bonding films in the Examples, while in ComparativeExample 1, 10×10 mm square and 15×15 mm square chips could not be pickedup, and in Comparative Example 2, 5×5 mm square, 10×10 mm square and15×15 mm square chips could not be picked up. As is evident from thethese test results, the dicing/die-bonding film having apressure-sensitive adhesive layer between a supporting base material andan adhesive layer wherein the adhesion between the adhesive layer andthe pressure-sensitive adhesive layer is lower in the wafer-attachingregion than in the other region (region onto which a wafer is not stuck)has the adhesion thereof to a dicing ring without failure in dicing, andchips of various sizes can be picked up well.

1. A dicing/die-bonding film comprising a pressure-sensitive adhesivelayer on a supporting base material and a die-bonding adhesive layer onthe pressure-sensitive adhesive layer, wherein releasability in aninterface between the pressure-sensitive adhesive layer and thedie-bonding adhesive layer is different between an interface (A)corresponding to a work-attaching region in the die-bonding adhesivelayer and an interface (B) corresponding to a part or a whole of aregion other than the work-attaching region, and the releasability ofthe interface (A) is higher than the releasability of the interface (B).2. The dicing/die-bonding film according to claim 1, wherein aadhesionof the pressure-sensitive adhesive layer to the die-bonding adhesivelayer is different between a region (a) corresponding to thework-attaching region in the die-bonding adhesive layer and a region (b)corresponding to a part or the whole of the other, and satisfies therelationship: the adhesion of the is lower than the adhesion of region(b).
 3. The dicing/die-bonding film according to claim 1, whereinadhesion of the work-attaching region in the die-bonding adhesive layerto a work and to the region (a) satisfies the relationship: the adhesionto the work is higher than the adhesion to the region (a).
 4. Thedicing/die-bonding film according to claim 1, wherein the part of theregion other than the work-attaching region in the die-bonding adhesivelayer is a dicing ring-attaching region.
 5. The dicing/die-bonding filmaccording to claim 4, wherein aadhesion of the dicing ring-attachingregion in the die-bonding adhesive layer to a dicing ring and to aregion (b′) corresponding to the dicing ring-attaching region satisfiesthe relationship: the adhesion to the dicing ring is lower than theadhesion to the region (b′).
 6. A dicing/die-bonding film comprising apressure-sensitive adhesive layer on a supporting base material and adie-bonding adhesive layer on the pressure-sensitive adhesive layer,wherein the die-bonding adhesive layer is arranged as a work-attachingregion on a part of the pressure-sensitive adhesive layer, and a regioncorresponding to the work-attaching region in the pressure sensitiveadhesive layer and a region other than the region (a) are different inadhesion and satisfy the relationship: the adhesion of the region (a) islower than the region (b).
 7. The dicing/die-bonding film according toclaim 6, wherein adhesion of the work-attaching region to the work andto the region (a) satisfies the relationship: the adhesion to the workis higher than the adhesion to the region (a).
 8. The dicing/die-bondingfilm according to claim 1, wherein the pressure-sensitive adhesive layeris made of a radiation-curing pressure-sensitive adhesive, and theregion (a) corresponding to the work-attaching region is irradiated withradiations.
 9. The dicing/die-bonding film according to claim 6, whereinthe pressure-sensitive adhesive layer is made of a radiation-curingpressure-sensitive adhesive, and the region (a) corresponding to thework-attaching region is irradiated with radiations.
 10. A method offixing a chipped work, comprising the steps of: pressing a work onto thework-attaching region of the die-bonding adhesive layer in thedicing/die-bonding film described in claim 1, dicing the work intochips, releasing the chipped work together with the work-attachingregion of the die-bonding adhesive layer from a region (a) of thepressure-sensitive adhesive layer corresponding to the work-attachingregion, and fixing the chipped work to a semiconductor element via thework-attaching region of the die-bonding adhesive layer.
 11. Asemiconductor device comprising a chipped work fixed onto asemiconductor element via the work-attaching region of the die-bondingadhesive layer by the method of fixing a chipped work as described inclaim
 10. 12. A method of fixing a chipped work, comprising the stepsof: pressing a work onto the work-attaching region of the die-bondingadhesive layer in the dicing/die-bonding film set forth in claim 6,dicing the work into chips, releasing the chipped work together with thework-attaching region of the die-bonding adhesive layer from the region(a) of the pressure-sensitive adhesive layer, and fixing the chippedwork to a semiconductor element via the work-attaching region of thedie-bonding adhesive layer.
 13. The method according to claim 10,wherein the pressure-sensitive adhesive layer is made of aradiation-curing pressure-sensitive adhesive, and the region (a) isirradiated with radiations.
 14. The method according to claim 12,wherein the pressure-sensitive adhesive layer is made of aradiation-curing pressure-sensitive adhesive, and the region (a) isirradiated with radiations.